The most widely used driveway sealer is a thick, black, coal tar emulsion. It is generally sold retail in large 50 pound metal or plastic pails with lids. In storage, the emulsion separates into a heavy paste topped by a layer of watery liquid. The degree of separation depends on the storage time and conditions, but the layer of supernatant liquid typically makes up 5% to 30% of the material by volume. Viscosities of the sealer and its separated components have been measured at 75.degree. F. with a Brookfield Syncho-Lectric viscometer Model RVT at 5 RPM using the Helipath stand for vertical travel. After about three weeks of settling, the settled paste has a viscosity of about 350,000 centipoises and after about six months the paste has a viscosity of about 600,000 centipoises. When mixed with the liquid, which has a viscosity of less than one centipoise, an emulsion having a viscosity of about 13,000 centipoises is obtained.
Mixing and dispensing the driveway sealer from a pail can be a very disagreeable task. The lid is often difficult to remove. Once the lid is removed, mixing of the heavy, settled paste with the thin, watery liquid is time consuming and inevitably results in messy spattering of the sealer onto the surrounding ground and onto the individual mixing the sealer. Once the sealer is thoroughly mixed, usually after about ten minutes of effort, it must be poured from the pail onto the driveway, and it must be smoothed out with a squeegee or brush. When poured, the sealer again spatters on the user as well as on any adjacent wall or the like. The spattered sealer is difficult to clean from the user's clothing or adjacent surface and is an irritant to the user's skin.
The primary object of this invention is to provide a means for mixing and dispensing a heavy emulsion such as driveway sealer with much less time, effort and mess than has heretofore been possible and without the need for a mixing implement.
Conventional pails for storing driveway sealer provide reasonable stacking strength and resist blows from the side. However, the rims of pails are easily crushed when dropped at an angle. This is a particular problem when attempting to carry heavy fluids such as 50 pounds of driveway sealer. When a rim of the bucket is crushed, the pail not only loses its stacking ability; it is also subject to leakage of the sealer. Other disadvantages of conventional pails include the cost of metal or plastic and the cost of forming the pails. Also, the stacking of cylindrical pails results in a substantial loss of storage space due to the voids between the stacked pails. The weight of the pails also contributes significantly to the cost of transporting the sealer. Finally, filling of the pails with the heavy emulsion is a time consuming process which does not readily lend itself to mechanization.
A further object of the present invention is to provide a package for storing emulsion such as driveway sealer which is relatively economical and durable and which lends itself to high density storage on pallets and the like and high speed filling.